Autoimmunity is where the body's own immune system attacks healthy cells and tissues within the body. This can result in many issues such as low thyroid, systemic pain in the muscles, and forms of arthritis.Usually those suffering from autoimmunity will have to take each day one day at a time. They could feel great today, and rundown tomorrow. This can make exercising a real challenge because you may not feel up for it.Julia Morichelli is a fitness trainer who also suffers from autoimmunity. She has been diagnosed with multiple autoimmune conditions, so she knows all too well how difficult exercising can be.